This application is a request for continuation of support for a pre-doctoral training program in Microbial Pathogenesis at Yale University. The program is overseen by a Director, Dr. Jorge Galan, and an executive committee of 5 Faculty members. The administrative entity of this training program is housed in the Department of Microbial Pathogenesis at the Yale School of Medicine. Forty-six faculty members from departments of the Yale Medical School and the Faculty of Arts and Sciences representing a cross-section of the microbial pathogenesis research community at Yale are involved in the program as trainers. The training Faculty carry out research in a broad range of topics that are directly relevant to microbial pathogenesis giving students unique opportunities to explore different aspects microbial pathogenesis research. Trainees are also provided with multiple opportunities for scientific interactions not only within their home Departments but also throughout Yale University. The goal of this program is to train students in multidisciplinary approaches to the study of microbial pathogenesis. The training faculty shares the view that the understanding of the biology of pathogenic microorganisms requires experimental approaches and concepts from different fields of science. Therefore the program seeks to provide students with the necessary broad experimental skills and knowledge that will allow them to pursue a future research career in the study of microbial pathogens. The existence of very strong basic science departments committed to this concept creates a unique environment in which this training program can flourish and produce superbly trained scientists. Significant improvements have been made to this training program. Starting Fall 2012, the students receive full institutional support (stipend, tuition and health benefits) from Yale University during their firs year, which includes formal course work and three research rotations. Therefore, no first year students will be appointed to the training Grant, thus ensuring the programmatic fit of the trainees appointed to this training program. Several new Faculty trainers and new courses have been added to the curriculum, further strengthening the training program. Finally, the creation of the Microbial Diversity Institute as well as other Institutes at the newly acquired Yale Universitys West Campus has enhanced the training opportunities for the students enlisted to this program. The training program consists of formal course work and laboratory rotations during the first two years. This provides a solid and broad conceptual foundation and knowledge base as well as broad experimental training through the laboratory rotations. Students select a research advisor during the second year and prepare and defend a research proposal that will serve as the foundation for the dissertation research project. A Thesis committee monitors the student progress throughout the thesis research process and, finally, the preparation of the dissertation. An External Advisory Board composed of highly accomplished scientists in the field of Microbial Pathogenesis has been appointed to monitor the progress of this training program. Students enter the program through the Combined Program in Biological and Biomedical Sciences (BBS). The BBS unites the more than 250 faculty in basic biological and biomedical sciences at the Yale Medical Scholl and Science Hill on the main University Campus. Admission is granted to students with outstanding academic record with particular attention to research experience. Given the new institutional support for the first year, the quality and depth of our pool of applicants, and the expansion of the training opportunities, we request funds to support 4 graduate students in years 2 and 3 (8 slots) for a five-year period.